Electric starter for internal-combustion engines.



A. H. MIDG-LEY. ELECTRIC STARTER FQR INTERNAL COMBUSTION ENGINES.APPLICATION FILED JULY 19.19l1.

1,254,923. Patefited Jan. 29,1918.

UNITED STATES PATENT OFFICE.

ALBERT HENRY MInGLEY, or ACTON VALE, ENGLAND, ASSIGNOR or or go 0. A.VANDERVELL AND COMPANY LIMITED, or ACTON VALE. ENGLAND.

i ELECTRIC STARTER FOB-.INTERNAL-COMBUSTION ENGINES,

72) all rirhom, it may concern:

Be it. known that 1". Aunzu'r l'Il-INl-Y Mioc- Lm', a subjcct ofthc Kingof (ircat Brit-- ain and Ireland. and residing at \Varplc \Vay. ActonYalv, in thc count of Middlescx. England, haw inrcntcd rvrtain now anduseful Improvements in and Relating to Electric Starters for TntcrnalCombustion Engincsfo'f which the follrnvim; is a specification.

Tll'is invention relates to an improved clcctric starter internalcombustion cugincs of the kin-l wherein the initial engagvmcnt' of thegoal members is effected by a longitmlinal .mo'yclncnt of tho armatureshaft; under magnetic action and the completion of thc' cngagcm'cnt bymeans of-n screw or helical conncction lictwccn the longitudinallrmorahlv armature shaft and the memberof tho g car carried by the latter,such as dcscribcd in British patent specification N 242953- of 1914. V

In stinrtcrs of the kind abore'rcferrml to, the longitudinal movement ofthe armature shaft is substantially reduced as compared I with thelongitudinal movement of the shaft in starters which are not providcd.with a screw or l clica'l dcvice andwhcrcin the one nicmbcr of'tlicgear is fixcdto said shaft', and one object of t'lie'prcsent. inventionis to further rcd'ucc the longitudinal movementof thefshafti; anotherobject bcing to improv t-he initial stage of operation of the sta rt'ingdevice;

3 \Vifth" these objects in view the invention consists in causing afriction disk or equivalent-.mcmber uscd in' conjunction with the pinionwhich is connected withithe longitudinally movable armature shaftthroughthe screw mhclical device to be brought intogfrlctional' contact withthe fly-wheel of thccngine or other lfltill'y' or stationarylnenibcrundcrslow rotation ofj thcclectric mot oi" and? bj awrylongitudinal.movement; of Its armnti n'o'slmft,prior to the 1 initial engagement ofth'c'toothcdmcml'icrs ofrthc gear, which latter cngngem'ent issubsequent-1y cifl'ccteda-ndl'complcted by the screw or hehcal deviceina known manner.

may 'citlierbe attached to the pinion-or'ar- The friction disk orequivalent: member ranqedto rotate'thcrcwith. while being ca: pab leoflmoving longitudinally relatively thereto; as has already" beenproposd'" in electric'starters wherein an ordinary motor is employed.thc shaft. of which is connected with tho pinion by means of a screw orhelical device but is not longitudinally movable as in the arrangementaccording to the pros out invcnt-ion and whcrcin the friction do vicccomes into operation before the initial cngagcmentof the gear mcmbvrs inorder to assist the cti'ect of the inertia of the. pinion and therebyinsure its operation and more particularly its'cngagcmcnt with the othermember of thc gcar. The arrangement according to the present inventiondiffers from thrse forms of construction which have previously beenproposed in that the short, longitudina'l.inorcmcnlz of the shaft 'underslow rotation is employed for initiating the' op yuration ofthestarl'cr, and not the inertia of the pinion and friction disk whichis dependent upon a rapid acceleration of the clccfric motor as is thecase in the known forms of construction.

Referring to the accompanying drawing which illustrates by way ofexample one mode of carryingtzhc invention into effect,-

a is the electric motor b its longitudinally vdisplaceahlc' armatureshaft, 0 a helically thrcadcd member suitably keyed to the armatureshaft, and (Z is a pinion which is mountcdin helical engagement with thehelically thrcadcd member 0 and is adapted to 006pcrate with a toothedring e provided on the f y-wheel of the engine to be started or on otherrotary member connectedor cooperating therewith.

f isii friction ring mounted on a'cOVer g 9 0 which is loosely supportedon the longitudinally movable nrmaturc'sha-ft b" i i-such a. manner aspositively to follow'the longitudinal displacement of the latter in oneor the 'othcr direction and thereby be brought into frictionalcngagcment with the side of the toothed ring 0 or'other rotary'orstationary part" ofthe engine} The pinion d is pro- .vided' with a:guiding pin h-j-arra-ngd slidingly to engage with the cover g. i is aspring interposed between a stationary part 'of the electric motor and-an abutmentj on tlie'iu'mature'ishnft and arrang'cdtoact in awcll'known manner durin the inward longit udinal movement of tic shaft andfor causin the outward d isplaccment thereof.

Instcad-of'mounting the friction ring f 0L a. member gf0 rming a coverfor the pinion (l as has previously been prpposed'the same may otherwisebe loosely-supported on the longitudinally movable shaft in such amanner that it shall follow the longitudinal displacement thereof, andthe details of con struction of the starter hereinbefore described mayotherwise be modified without in any way departing from the spirit ofthe invention.

What I claim is An electric starter for internal combustion enginescomprising in combination an electric motor havin an armature shaftcapable of longitudlnal displacement, a toothed gear,.one member ofwhich is connected with the en ine to be started while the other membertiereof consists of a helically threaded pinion, a helical thread on thelongitudinally displaceable armature shaft in engagement with thehelically threaded pinion, and a friction device constituted by twomembers, one of which is sup )orted on the longitudinally displaceablesha t so as to be capable of relative rotation thereon, together withthe hclically threaded pinion, and be compelled positive] to follow thelongitudinal displacement o" the armature shaft, the distance betweenthe members of the friction device being shorter than the distancebetween the members of the toothed gear, whereby the friction device isbrought into operation during the lon 'itudinal displacement of thearmature shaft and before the initial engagement of the members of thetoothed gear, as set forth. In testimony whereof I have signed my nameto this specification.

ALBERT HENRY MIDGLEY.

